So the old duster made the trip to Tallahassee. Ive transfered into Fsu and will be up here for the next year or two. During my drive at highway speeds I noticed my bov staying open once i was maintaining speed and was just curious if anyone knew some things about the effect on mpg if any or on the turbo while its just spinning at constant speed with the bov open. Just for some past information i'm using a piston style synchonic bov built by synapse, its designed to stay open at idle and operates normally while driving but under very light load at highway speed the bov will actually just stay open hissing from the positive pressure from the turbo. I'm not worried about but I can't seem to find any theory or research about whether it would be better off having the bov closed for that bit of pressure to stay in the system or is it a mute point.

Thanks,
Kev

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Let me begin with "AWESOME FRIGGIN' WORK!"

With that out of the way, BOVs are usually tied to manifold vacuum/boost. It appears your's is, as it is open at idle (high vacuum). You probably have enough vacuum to get the thing to open at cruise. This is a good thing! That means it takes little throttle to maintain speed and fuel economy is good.

Since you have a blow-thru set-up, having the BOV open won't hurt a thing. You aren't spewing raw fuel into the air.

Glad you're enjoying the fruits of your labors. Keep us posted through the fine-tuning stage.

Mike

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Recognized by US Federal Courts as a Fuel Economy Expert!

Thanks! man its always nice to get praise for many long nights of hard work. Ya i figured it was fine considering if the motor was making more power with the bov closed it would most likely be using more fuel because of slight boost. It runs good when you beat on it and the drivabilty is always getting better the more I tinker with the tune.
Stretched its legs a little bit during the late night highway driving up here
6,000rpm in 4th 1:1 with a 28inch tired and 3.73s out back

Kev

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